Re: Ada Examples and Problems

["chris.danx" <chris.danx@ntlworld.com>]

> >It works on a sequential read but not on a non-sequential read.
>   "For direct access, the file is viewed as a set of elements
> occupying consecutive positions in linear order;..."  LRM A.8(3)
> So each element of a direct access file must be the same size.
> Since you have owner, dog, owner, dog... where owner and dog are
> different size records, that won't work.  But "Pair" in
>   type Pair is
>     Person : Owner;
>     Animal : Dog;
>   end record;
> is a constant size record.  If you want the N-th owner, or N-th dog,
>   Set_Index(The_File, N);
> That seems easier than taking the individual byte as the constant
> size element and then doing arithmetic that you hope gets you to
> the correct byte position.

Thanks for that I'll use it in future.

The reason i did it with two different sized records was because I'm writing
a driver for a file system.  It's contigouous which means i've got to do all
sorts of mad calculations and access the stream.  It's not fun.

Thanks again,
Chris Campbell
http://willow.os-4u.com